Two Actions to Improve S3 Bucket Security
Which TWO actions will improve the security posture of an Amazon S3 bucket used to store sensitive data? (Choose two.)
Quick Answer
The answer is enabling S3 Block Public Access and configuring a bucket policy that denies access unless the request originates from a specific VPC or IP range. These two actions directly enforce network-level and account-level restrictions, preventing unauthorized access at the bucket’s perimeter. S3 Block Public Access acts as a centralized override that blocks all public access policies, while a condition key like aws:SourceIp in the bucket policy ensures only traffic from trusted IPs or VPC endpoints can reach the data. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this pairing tests your understanding of defense-in-depth for sensitive data—a common trap is confusing encryption or logging with access control, which do not block unauthorized requests. Remember the memory tip: “Block first, then lock the IP” to recall that S3 Block Public Access is the global kill switch, and the bucket policy is the granular gatekeeper.
⚠ Common exam trap
A common mix-up: candidates confuse data protection features like Versioning and encryption with access control mechanisms, leading them to select options that protect data integrity or confidentiality at rest but do not prevent unauthorized access or exposure.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable S3 Block Public Access settings at the account or bucket level.
S3 Block Public Access settings provide a centralized, account- or bucket-level control that overrides any bucket policies or object ACLs that would grant public access, effectively preventing data exposure. Option E is correct because a bucket policy condition that restricts access to requests originating from a specific VPC or IP range limits the attack surface by ensuring only authorized network paths can reach the bucket, which is a key security best practice for sensitive data.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable S3 Versioning on the bucket.
Why it's wrong here
Versioning protects against overwrites but not unauthorized access.
- ✓
Enable S3 Block Public Access settings at the account or bucket level.
Why this is correct
Block Public Access prevents any public access, improving security.
- ✗
Enable default encryption using SSE-S3.
Why it's wrong here
Encryption protects data at rest but does not control access.
- ✗
Enable S3 server access logging for the bucket.
Why it's wrong here
Logging helps with auditing but does not prevent unauthorized access.
- ✓
Configure a bucket policy that denies access unless the request originates from a specific VPC or IP range.
Why this is correct
Restricting access by source IP or VPC limits exposure.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
Related to this question
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Same concept, more angles
1 more way this is tested on SAP-C02
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Variation 1. Which TWO actions improve the security of an Amazon S3 bucket that stores sensitive data?
medium- A.Enable CORS (Cross-Origin Resource Sharing).
- ✓ B.Enable S3 server access logging.
- ✓ C.Enable S3 Block Public Access.
- D.Enable S3 Transfer Acceleration.
- E.Use a bucket policy that denies access to all principals except the root user.
Why B: Enabling S3 Block Public Access (Option C) is a critical security control that prevents any public access to the bucket, regardless of bucket policies or object ACLs, effectively eliminating the risk of unintended data exposure. Enabling S3 server access logging (Option B) records all requests made to the bucket, providing an audit trail that can be used to detect unauthorized access attempts, troubleshoot security events, and meet compliance requirements. Both actions directly enhance the security posture of a bucket storing sensitive data.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.